Various mechanisms have long been utilized to clean textiles with the use of non-aqueous cleaning solvents. These devices have generally been called "dry cleaning" machines and are comprised of a rotating drum into which garments are placed. A variety of mechanisms for introducing and removing the cleaning solvent may be used. During the cleaning process the cleaning solvent is "contaminated" with various substances including dirt and grime, dyes, "spotting" substances and body oils. In addition, a measurable amount of water is introduced to the cleaning process through several sources, including moisture that may be naturally contained in the textiles, water added during the spotting process, and humidity in the air in the machine. This water mixes with the cleaning solvent, or its vapors, during the cleaning and drying cycle.
Following the wash cycle, the textiles are dried by draining off the liquid solvents and subsequently blowing heated air over the garments to vaporize and carry away solvents contained in them. This vaporized solvent, containing some water, is then condensed using a cooling process. A liquid mixture of cleaning solvent and water is obtained from this process. In addition, the dry cleaning machine also distills the cleaning solvent to help remove oils, dyes and the like from it. This distilling produces a condensate mixture of water and solvent. A separating device on the dry cleaning machine is then employed to separate the solvent from the water resulting from both of these processes so that the solvent may be reused. The remaining water is unfortunately contaminated with a certain amount of cleaning solvent that was not able to be separated out. As is noted in U.S. Pat. Nos. 2,438,868 and 3,104,936, the separation process, while subject to improvement is not perfect.
The contaminated water recovered from the dry cleaner operation must be disposed of. Historically, it was simply dumped into a sewage system. However, with the advent of stricter environmental standards, this is now often prohibited.
It has also been known to evaporate the contaminated water through boiling since the small amounts of cleaning solvent thus vaporized into the work environment may be within applicable air quality standards. However, this boiling method requires a complex and expensive boiler mechanism, requires the expenditure of fuel resources, poses safety problems, and creates additional emissions problems if a fossil fuel is used to fire the boiler.
The present invention provides apparatus and techniques to overcome these severe environmental and economic restrictions through a novel, effective and safe method of disposal of the contaminated water.
Another problem associated with the use of conventional dry cleaning apparatus is evident after the cleaning cycle is complete. When the access door is opened to permit removal of the cleaned garments or textiles, solvent vapors in the cleaning drum can escape through the access door into the surrounding environment and particularly into the area where operating personnel are working. This presents environmental and safety problems as well as presenting offensive odors to the work place. Apparatus and techniques for eliminating or reducing escape of the solvent vapors are described in commonly assigned copending application Ser. No. 07/719,261, incorporated herein by reference.